import java.util.*;

public class Main {
    
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        String ans = "";
        if( s.equals("E") ) {
            ans = "F";
        }else if( s.equals("B") ) {
            ans = "C";
        }else {
            ans = s+"#";
        }
        
        System.out.println(ans);
        
    }
    
}